1. Field of the Invention
The present invention relates to a method and apparatus for facilitating the repair of leaks in water lines, particularly, buried water sprinkler lines.
2. Description of the Prior Art
Presently, buried water sprinkler lines are widely employed as a means for watering lawns, flower beds, golf courses, plant seedlings, and for other applications. The conventional practice in installing buried water sprinkler systems is to bury lengths of water sprinkler pipe in a pattern emanating from a water supply, and to provide risers at spaced intervals. sprinkler heads are located at the risers to sprinkle water throughout predetermined areas. Conventional water sprinkler lines are typically buried at depths governed by climate extremes in the geographic area in which the sprinkler system is located and by surface activities which are likely to occur above the buried sprinkler lines. Water lines can be buried at a relatively shallow depths in climates which are not subject to freezing temperatures and at locations where the surface is likely to remain undisturbed. In contrast, sprinkler lines are buried much deeper at geographic locations which are subject to freezing and subfreezing temperatures, and beneath surfaces across which vehicles, such as tractors or lawn mowers are likely to travel.
While initially metal pipes were employed as the primary conduits in buried water sprinkler systems, modern sprinkler systems are constructed primarily of polyvinyl chloride piping, ducts and couplings. Polyvinyl chloride conduits and fittings are significantly cheaper to manufacture than are metal pipes, and are largely insensitive to substances in the soil which tend to corrode and degrade metal pipes.
Ideally, once a buried water sprinkler system is installed the buried conduits, pipes, fittings, risers, and sprinkler heads will remain undisturbed indefinitely. However, as a practical matter leaks do develop in buried water sprinkler lines for a number of different reasons. Such leaks are typically detected as a result of localized saturation of soil or due to observation of an unusually great consumption of water. When leaks in a water sprinkler system are detected, they must be repaired. If a leak occurs in a fitting or valve, the leaky fitting or valve must be removed and replaced. Alternatively, if a leak occurs at a location in a water pipe or duct, a section of the pipe or duct must be removed and replaced with a splice or coupling.
When leaks are detected in a buried water sprinkler system it is necessary to dig away soil from atop the water sprinkler line a considerable longitudinal distance along the piping in both directions from the source of the leak. The linear length of buried pipe line which must be exposed will vary depending upon the depth at which the pipe is buried, the nature of the soil, the looseness or compactness of the soil, and the extent to which the pipe line is accessible in both directions from the source of the leak along the buried water line. Nevertheless, the linear length of pipe which must be exposed is rarely less than about eight inches in both directions from the leaking section to be replaced and more typically is at least a foot in both directions. Moreover, to achieve the necessary exposure of the buried pipe line, excavation at the surface above the pipe must be performed over a considerably greater linear distance. Naturally, any plant or ground cover growth atop the length of buried water sprinkler line to be exposed must be destroyed. Thus, repair of an extremely localized leak in a buried water sprinkler line can involve the extensive destruction of substantial areas of a garden or lawn.
The reason that it is necessary to expose significant lengths of buried water pipe in both directions from the source of a leak is so that enough pipe is exposed so that the ends of the pipe in both directions from the source of the leak can be flexed sufficiently to allow a replacement fitting or a repair splice of fixed length to be inserted into the water line once the leaking fixture or the leaking portion of the pipe has been removed. In order for a replacement fitting or a splice to be inserted between exposed ends of a water line on either side of a leak, the replacement fitting or splice must be of a length greater than the distance of separation between the exposed ends of the water line so that the fitting or splice will more than span the distance of separation between the exposed ends. Some means of sealing, such as solvent welding is employed so that the overlapping ends of the replacement fitting or splice are securely joined to the exposed ends of the buried pipe on either side of a leak. However, in order for a replacement fitting or splice to be inserted in the line, the pipe must be flexed considerably to temporarily increase the distance of separation between the exposed pipe ends, so that the conventional, rigid replacement fittings or splices can be inserted therebetween.
One further disadvantage of the conventional technique for repairing leaks in lawn sprinkler repair lines is that the stress on the pipe which results from flexing the exposed lengths of pipe will often be transmitted along the length of the pipe and will result in a leak at a different location in the buried water sprinkler line. Thus, the conventional technique of repairing one leak in a water sprinkler line frequently results in creating a leak at a different location along the line.
A further disadvantage of the conventional buried water sprinkler line repair technique is that when the pipe is flexed and the replacement coupling or splice is inserted, the exposed end of the pipe and at least one end of the replacement fitting or splice must necessarily meet at a significant oblique angle, rather than in coaxial alignment. The exposed end of the pipe is thereby forced into an end of a replacement fitting or splice at some angle of displacement from the longitudinal axis of the replacement fitting or splice. This results in excessive manipulation between the exposed pipe end and the end of the replacement fitting or splice into which the exposed end of the pipe is inserted during curing of the solvent cement, so that the subsequent seal therebetween is more likely to leak.